P-POSSUM Score

Determines operative mortality risk for general emergency or elective surgery.

Refer to the text below the calculator for more information about the P-POSSUM score.

The Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) is the modified version of the original POSSUM Score that retains the same variables but uses a different mortality predictor equation.

The score evaluates mortality risk in patients due for emergency or elective surgery and should be computed at time of surgery, based on readily available clinical data.

The score is not indicated for trauma patients nor can be used in predicting mortality after trauma surgery.

The P-POSSUM score consists of two components, a physiological score and an operative score that are used to compute the operative mortality risk:

LogeR/1-R = -9.065 + 0.1692 x Physiological Score + 0.155 x Operative Severity Score

Physiological Score

1

Age

2

Cardiac signs | Chest X-ray

3

Respiratory signs | Chest X-ray

4

Systolic blood pressure (mmHg)

5

Pulse (beats/min)

6

Glasgow coma score

7

Urea nitrogen (mmol/L)

8

Sodium (mEq/L)

9

Potassium (mEq/L)

10

Haemoglobin (g/dL)

11

WCC (x1012/L)

12

Electrocardiogram

Operative Score

13

Operative magnitude

14

No. of operations within 30 days

15

Blood loss per operation (mL)

16

Peritoneal contamination

17

Presence of malignancy

18

Timing of operation

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The P-POSSUM Score explained

The Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) is the modified version of the original POSSUM Score that retains the same variables but uses a different mortality predictor equation.

The score evaluates mortality risk in patients due for emergency or elective surgery and should be computed at time of surgery, based on readily available clinical data.

The score is not indicated for trauma patients nor can be used in predicting mortality after trauma surgery.

In 1998, Prytherch et al. developed a more accurate scoring equation for the mortality component, whilst retaining the 12 physiological score parameters and 6 operation severity parameters.

This came following the need to adjust the logistic regression analysis used in POSSUM scoring to better predict mortality.

The study by Prytherch et al. found that the original POSSUM logistic regression equation for mortality overpredicted the overall risk of death by more than twofold (in patients at lowest risk <5% overpredicted by more than sevenfold).

The study collected data from 10,000 general surgical interventions, the first 2,500 being used as a training set to produce the modified P-POSSUM predictor equation, whilst on the remainder, the predictive properties of the score were tested. The P-POSSUM equation produced a very close fit with the observed in-hospital mortality.

Physiological Score
Variable 1 point 2 points 4 points 8 points
Age ≤ 60 61-70 ≥ 71  
Cardiac signs
Chest X-ray		 Normal
Normal		 Cardiac drugs or steroids
…		 Oedema; warfarin
Borderline cardiomegaly		 Jugular venous pressure
Cardiomegaly
Respiratory signs
Chest X-ray		 Normal
Normal		 Shortness of breath on exertion
Mild chronic obstructive airway disease		 Shortness of breath on stairs
Moderate chronic obstructive airway disease		 Shortness of breath at rest
Any other change
Systolic blood pressure (mmHg) 110-130 131-170 or 100-109 ≥ 171 or 90-99 ≤ 89
Pulse (beats/min) 50-80 81-100 or 40-49 101-120 ≥ 121 or ≤ 39
Glasgow coma score 15 12-14 9-11 ≤ 8
Urea nitrogen (mmol/L) < 7.5 7.6-10 10.1-15 ≥ 15.1
Sodium (mEq/L) > 136 131-135 126-130 ≤ 125
Potassium (mEq/L) 3.5-5 3.2-3.4 or 5.1-5.3 2.9-3.1 or 5.4-5.9 ≤ 2.8 or ≥ 6
Haemoglobin (g/dL) 13-16 11.5-12.9 or 16.1-17 10-11.4 or 17.1-18 ≤ 9.9 or ≥ 18.1
WCC (x1012/L) 4-10 10.1-20 or 3.1-3.9 ≥ 20.1 or ≤ 3  
Electrocardiogram Normal   AF (60-90) Any other change
Operative Score
Variable 1 point 2 points 4 points 8 points
Operative magnitude Minor Intermediate Major Major+
No. of operations within 30 days 1   2 > 2
Blood loss per operation (mL) < 100 101-500 501-999 > 1000
Peritoneal contamination No Serious Local pus Free Bowel content, pus or blood
Presence of malignancy No Primary cancer only Node metastases Distant metastases
Timing of operation Elective   Emergency resuscitation possible, operation <24h Emergency immediate operation <2h

The P-POSSUM equation for mortality risk:

LogeR/1-R = -9.065 + 0.1692 x Physiological Score + 0.155 x Operative Severity Score

Examples of magnitude for general surgery:

  • Minor: hernia, varicose vein, minor perianal surgery, scrotal surgery, minor transurethral resection of tumor, excision of large subcutaneous lesion;
  • Intermediate: open cholecystectomy, laparoscopic cholecystectomy, appendectomy, excision of lesion requiring grafting or minor excision, minor amputation, thyroid lobectomy;
  • Major: laparotomy and small-bowel resection, colonic resection or anterior resection, major amputation, nonaortic vascular surgery, cholecystectomy and exploration of bile duct, total thyroidectomy;
  • Major+: abdominoperineal excision of rectum, aortic surgery, whipple resection, radical total gastrectomy;

There are other perioperative morbidity and/or mortality risk predictors available, either for general surgery or for specific diseases and morbidities:

  • The Surgical Apgar Score (SAS) offers a morbidity and mortality risk estimation and whilst it is deemed more objective than POSSUM, it is less comprehensive (uses only 3 intraoperative variables) whilst POSSUM uses several more preoperative variables.
  • The APACHE II model estimates risk of mortality in intensive care patients.
  • The Revised Cardiac Risk Index (RCRI) estimates risk of perioperative cardiac events in patients undergoing heart surgery.
 

References

Original reference

Prytherch DR et al. POSSUM and Portsmouth POSSUM for predicting mortality. Br J Surg. 1998; 85:1217-20.

Validation

Tran Ba Loc P, du Montcel ST, Duron JJ, et al. Elderly POSSUM, a dedicated score for prediction of mortality and morbidity after major colorectal surgery in older patients. Br J Surg. 2010; 97(3):396‐403.

Other references

Scott, S., Lund, J.N., Gold, S. et al. An evaluation of POSSUM and P-POSSUM scoring in predicting post-operative mortality in a level 1 critical care setting. BMC Anesthesiol 14, 104 (2014).

Specialty: Emergency

No. Of Variables: 18

Year Of Study: 1998

Abbreviation: P-POSSUM

Article By: Denise Nedea

Published On: June 1, 2020 · 12:00 AM

Last Checked: June 1, 2020

Next Review: June 1, 2025